All the best supermarket bargains this week - including where to get your Christmas tree

If you know where to shop this week, a $20 note could buy you a kilo of carrots, tomato sauce, a can of baked beans, 100 Twinings tea bags, four mangoes, some hommus and two litres of ice cream.

But you can also get some pretty luxurious Christmas gifts and supplies at low prices by shopping around, such as $9 lobster tails, a $40 195cm Christmas tree, a $299 inflatable water park, a $49.50 capsule coffee machine and half-price Bonds undies and socks.

One Big Switch has picked out 'Australia's cheapest grocery basket this week', filled with the best bargains going live at Coles, Woolworths and Aldi on Wednesday, December 1.

For full details of these specials and our methodology, go to our new home of grocery bargains at this link, where One Big Switch has scoured the latest catalogues so you don't have to.

Shoppers can use this list as the starting point for their own and pick and choose where they shop based on which specials they really want this week.

READ MORE: The best meat pie in Australia

Who has the best bargains this week?

Shop at Aldi for the cheapest mangoes (4 for $6), avocados (99c each), carrots (99c/kg), tomato sauce ($1.49), ibuprofen ($2.39 for 20) and hommus ($1.49).

Aldi's also got Christmas gifts such as a Hot Wheels slot track ($40), Crayola colouring sets ($3), inflatable water parks ($299), and a $30 bluetooth floating light speaker for those after-hours pool parties. On Saturday there's an $80 wifi tower fan or a $40 pedestal fan.

Shop at Coles for the cheapest rice ($10 for 5kg), ice cream ($4.25 for 2L), Vittoria coffee ($8.50 for 500g), paper towel (4 for $2.75) and Heinz baked beans ($1).

READ MORE: How a brave 17-year-old saved her 12 siblings from a lifetime of abuse

Coles also has half-price Bonds undies and socks, half-price toiletries by Koi for Men, Sukin & Nivea, 15 per cent off gift cards from Hoyts, RedBalloon, Gourmet Traveller Restaurant & Kayo, and a refurbished Apple Watch series 4 for $379.

Shop at Woolies for the cheapest corn ($2.50 for 3), grapes ($9.50/kg), olive oil (3L for $18), Twinings tea bags ($5.60 for 100) and energiser batteries (16 AAA for $12).

Woolies also has a 195cm Christmas tree for $40, stockings stuffed with chocolate for $4.80, $9 lobster tails, a capsule coffee machine for $49.50, half-price Garnier and L'Oreal products, and a huge 66 per cent off amaysim $30 mobile starter packs.

Click here to see all this week's deals

READ MORE: Miniscule dress at father's wedding goes viral with 4m views

How do we choose?

We have not listed every special or 50 per cent discount from all 3 supermarkets, nor every low price.

To simplify things, we've boiled it down to what we consider the best specials and everyday prices advertised on the most popular grocery products, based on information provided by Coles, Woolworths, Aldi and the Australian Bureau of Statistics.

To decide which specials were the winners this week, we looked at a combination of unit pricing, practicality of packaging size, popularity and seasonality.

If an everyday price was cheaper than all the specials this week, we chose the everyday priced item unless stated.

Where two supermarkets have identical or very close prices on similar products, such as Smiths Crisps and Doritos, we've called it a tie.

We've based our analysis on catalogues for Sydney, postcode 2000 — but be aware that catalogues in some states may differ.

Useful links

"Australia's Cheapest Grocery Basket", revealed every Wednesday

Coles:

Click here for all this week's specials in your postcode

FREE Delivery for first-timers and on all orders over $250

Woolies:

Click here for all this week's specials in your postcode

FREE Delivery for first-timers and on all orders over $300

Aldi:

Click here for all this week's specials in your postcode

Joel Gibson is a TODAY regular, Nine Newspapers columnist and campaign director at OneBigSwitch.com.au